The present invention relates to an apparatus for detecting coordinates. Conventionally, an apparatus for detecting coordinates on a surface is known, in which conductive films are disposed in parallel and in opposition to each other with a slight space therebetween, and both conductive films are provided with electrodes causing currents to flow into the respective conductive films. This apparatus is arranged, for example, such that the apparatus is placed on a flat surface on which for example a video image is projected and a desired position (coordinate) on the video image is depressed (touched) from above the upper surface of the overlapped conductive films by using, for example, a thin pen point, so that a signal corresponding to the coordinate at the depressed position is derived through the electrodes and inputted to a computer or the like.
This apparatus is, however, disadvantageous in that reliability as well as accuracy in coordinate detection is not so high.
Further, an apparatus has been proposed in which the layers, each having a plurality of conductive portions separated by insulator portions extending in the same direction, are overlapped with a space therebetween such that the conductive portions of one of the layers are perpendicular to the conductive portions of the other layer, the layers being flexible so that they may electrically contact each other when depressed to thereby form a matrix type switching function.
Since in the thus arranged apparatus, two potentials or a set of a potential and a time point corresponding to the coordinate to be detected are detected, the apparatus is disadvantageous in that when the coordinate information is transferred to a computer, the interface for coordinate detection as well as the software for data transmission to the computer are complicated.
When this apparatus is used for detecting two-dimensional coordinates, there is a further disadvantage in that a lot of electrodes are required and therefore the reliability in coordinate detection is low and the resolution power is small.